I have a razer blackwidow ultimate 2013, that has a non standard layout of the last row: the ctrl and the alt seem to be size 1.5 (the same size as the tab keycap), there are other 3 normal one sized buttons and the space bar, that seems to be 6x. So if I understood properly there's nothing to do for the space bar, but for the other buttons I could go for the rgb kit or for the winkeyless one? Am I wrong?

Thank you for the reply! I have a razer keyboard since 2013, it's not a bad keyboard, its only problem was the cost, and that's the point: I bought this keyboard on impulse because razer for a day had a 50% price discount, so browsing the store I found that this keyboard and for that price (around 100€ if I recall correctly) it seemed a good value! The only problem I had with this keyboard is that it has a US layout, and since I fell in love for those keycaps I mentally justified the price on the fact that I could finally make accented letters without having to guess (I am italian, so those letters are quite common)! Anyway the plan is now to fit those keycaps on this keyboard, and slowly starting to search a more proper keyboard to put them on (I know it would be awkward to put keycaps coming straight from the '70 to a space age looking keyboard). At the end being that the shipping will be in october, I may be able to put them straight to the final keyboard!